[Bug] ECharts connect() does not link the last data point across connected charts

### Version

5.4.2

### Link to Minimal Reproduction

Please refer to the images in the description.

### Steps to Reproduce

I am using ECharts echarts.connect() to link tooltip and axisPointer interactions across four charts (Chart 1, Chart 2, Chart 3, and Chart 4).
All charts share the same timestamp-based x-axis data, and all charts are assigned to the same group.

In general, the connected charts work as expected.
However, there is a consistent issue where the last data point on Chart 3 or Chart 4 does not link to Chart 1 and Chart 2.

### Current Behavior

**Observed Behavior**
Chart 1/2 → Chart 3/4: the last data point links correctly

Chart 3/4 → Chart 1/2: the last data point does NOT link

All other data points link normally

This behavior occurs only on the last data point and only for specific charts (typically Chart 3 or Chart 4).

**Additional Details**

After using dataZoom:

The second-to-last data point still links correctly

When this point becomes the last visible point, the linking issue appears again

Does this suggest that the issue is related to the final axis position or x-axis boundary behavior? I have also tried adjusting the grid size, but the same problem still occurs.

### Expected Behavior

When hovering the last data point on any chart in the group, all charts should show the corresponding tooltip/axisPointer through the connect() mechanism.

### Environment

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### Any additional comments?

_No response_